| abstract |
A process for producing an optically active isomer of a compound represented by the formula (II) (II) (wherein ring A represents an optionally substituted benzene ring; R1 represents hydrogen, an optionally substituted hydrocarbon group, acyl, or acyloxy; R2, R3, and R4 each represents hydrogen, optionally substituted alkyl, optionally substituted alkoxy, or optionally substituted amino; X represents nitrogen or CH; Y represents nitrogen or CH; and * indicates an asymmetric center) or of a salt of the compound, characterized by reacting a compound represented by the formula (I) (I) (wherein the symbols have the same meanings as the above) or a salt thereof with an excess of an oxidizing agent in the presence of a catalyst for asymmetry induction. This process is a simple process by which an optically active sulfoxide derivative can be efficiently and industrially mass-produced in high yield while attaining an extremely high enantiomer excess. |